Compressor and vacuum machine

ABSTRACT

A compressor includes: a cylinder; a piston arranged within in the cylinder; an outer rotor type motor causing the piston to reciprocate within the cylinder; an air pipe communicated with the cylinder such that air flows into the air pipe in response to reciprocation of the piston; and a fan secured to a rotor of the outer rotor type motor and facing at least a part of the air pipe.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2012-040415, filed on Feb. 27, 2012, and the prior Japanese Patent Application No. 2013-005703, filed on Jan. 16, 2013, the entire contents of which are incorporated herein by reference.

BACKGROUND

(i) Technical Field

The present invention relates to a compressor and a vacuum machine.

(ii) Related Art

There is known a compressor and a vacuum machine which compress and discharge intake air by a piston which reciprocates within a cylinder by a motor. Japanese Patent Application Publication No. 2004-183498 discloses such a compressor.

Air is adiabatically compressed within the cylinder, so that the temperature of the adiabatically compressed air becomes high. Thus, the compressor or the vacuum machine might be continuously used while heating up. In this case, for example, the piston wears to adversely influence parts and the life of the compressor itself or the vacuum machine itself. Also, there is a case where the compressed air blew a catalyst to react, depending on a device supplied with the compressed air. In such a case, when the compressed air temperature is high, the reaction of the catalyst might not proceed.

Japanese Patent Application Publication No. 2004-183498 discloses a fan for cooling the compressor is arranged in an axial direction of a motor. However, there is a problem with the large height in the axial direction. Further, in Japanese Patent Application Publication No. 2004-183498, an inner rotor type motor is used. Thus, there is another problem that the inner rotor type motor has a torque smaller than that of an outer rotor type motor having the same size as the inner rotor type motor.

SUMMARY

According to an aspect of the present invention, there is provided a compressor includes: a cylinder; a piston arranged within in the cylinder; an outer rotor type motor causing the piston to reciprocate within the cylinder; an air pipe communicated with the cylinder such that air flows into the air pipe in response to reciprocation of the piston; and a fan secured to a rotor of the outer rotor type motor and facing at least a part of the air pipe.

According to another aspect of the present invention, there is provided a vacuum machine includes: a cylinder; a piston arranged within in the cylinder; an outer rotor type motor causing the piston to reciprocate within the cylinder; an air pipe communicated with the cylinder such that air flows into the air pipe in response to reciprocation of the piston; and a fan secured to a rotor of the outer rotor type motor and facing at least a part of the air pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external view of a compressor according to a first embodiment;

FIG. 2 is an external view of the compressor according to the first embodiment;

FIG. 3 is an external view of the compressor according to the first embodiment;

FIG. 4 is a sectional view taken along A-A line of FIG. 1;

FIG. 5 is an external view of a compressor according to a second embodiment;

FIG. 6 is an external view of a compressor according to the second embodiment;

FIG. 7 is a sectional view taken along B-B line of FIG. 5;

FIG. 8 is an external view of a compressor according to a third embodiment;

FIG. 9 is an external view of a compressor according to the third embodiment;

FIG. 10 is an external view of a compressor according to a fourth embodiment; and

FIG. 11 is an external view of a compressor according to the fourth embodiment.

DETAILED DESCRIPTION

Plural embodiments will be explained.

First Embodiment

FIGS. 1 to 3 are external views of a compressor A according to a first embodiment. Additionally, an object device is connected at the exhaust side of the compressor A as will be described in detail. When the object device is connected at the intake side of the compressor A or when a check valve is arranged in a manner opposite to a manner of the compressor A, the compressor A acts as a vacuum machine. The compressor A includes: four cylinders 10 a to 10 d; a crankcase 20 attached with the four cylinders 10 a to 10 d; a motor M arranged at the upper side of the crankcase 20; a fan F attached with the motor M; and an air pipe 80 communicated with the cylinders 10 a to 10 d. The fan F rotates in response to the rotation of the motor. The cylinders 10 a to 10 d are attached around the crankcase 20. As illustrated in FIG. 1, the cylinders 10 a to 10 d are radially arranged about the rotational shaft 42 at even intervals. The rotational shaft 42 is a rotational shaft of the motor. The cylinder 10 a includes: a cylinder body 12 a attached with the crankcase 20; and a cylinder head 15 a attached with the cylinder body 12 a. The other cylinders 10 b to 10 d have the same structure. The air pipe 80 is connected with the cylinder head 15 a. This will be described later in detail.

The air pipe 80 is provided outside the cylinders 10 a to 10 d and the crankcase 20, and is provided around the cylinders 10 a to 10 d. The air pipe 80 includes branched pipes 81 a to 81 d respectively communicated with the cylinders 10 a to 10 d. Specifically, the branched pipes 81 a to 81 d are communicated with the cylinder heads 15 a to 15 d, respectively. The branched pipes 81 a and 81 b are connected with each other by a connection pipe G. Likewise, the branched pipes 81 b and 81 c, the branched pipes 81 c and 81 d, and the branched pipes 81 d and 81 a are connected with each other by the connection pipes G, respectively. In the above way, the branched pipes 81 a to 81 d are connected with one another. Additionally, the connection pipe G is made of rubber, but is not limited to this. The branched pipes 81 a to 81 d have substantially the same size and shape.

The air pipe 80 will be described in detail. As illustrated in FIG. 3, the branched pipe 81 a includes: a joint portion 85 a connected with a bottom surface of the cylinder head 15 a; a branched portion 84 a branched from the joint portion 85 a, extending in the direction perpendicular to the rotational shaft 42, and arranged at the bottom side of the cylinder head 15 a. A nozzle 89 is provided at the middle of a path portion extending toward the branched portion 84 d. As illustrated in FIG. 2, the branched pipe 81 b includes: a joint portion 85 b connected with an upper surface of the cylinder head 15 b; a branched portion 84 b branched from the joint portion 85 b, extending in the direction perpendicular to the rotational shaft 42, and arranged at the upper side of the cylinder head 15 b. As illustrated in FIG. 1, the branched portions 84 a and 84 b extend in the perpendicular direction. Additionally, the upper surfaces of the cylinder heads 15 a and 15 b mean surfaces facing the fan F.

As illustrated in FIG. 3, one end side of the branched portion 84 a is formed with a portion extending toward the cylinder 10 b, and an end continuous with this portion and extending toward the fan F in the axial direction of the rotational shaft 42. The other end side of the branched portion 84 a is formed with a portion extending toward the cylinder 10 d, and an end continuous with this portion and extending toward the fan F in the axial direction of the rotational shaft 42.

As illustrated in FIG. 2, one end side of the branched portion 84 b is formed with a portion extending toward the cylinder 10 c, and an end continuous with this portion and extending opposite to the fan F in the axial direction of the rotational shaft 42. The other end side of the branched portion 84 b is formed with a portion extending toward the cylinder 10 a, and an end continuous with this portion and extending opposite to the fan F in the axial direction of the rotational shaft 42.

As illustrated in FIG. 1, one end of the branched portion 84 b is connected with the other end of the branched portion 84 a through the connection pipe G. The connection pipe G extends in the axial direction of the rotational shaft 42. This connection pipe G is located between the cylinders 10 a and 10 b. In such a way, the branched pipes 81 a and 81 b are connected with each other.

Likewise, the other branched pipes 81 c and 81 d have the same structure. The branched portion 84 c of the branched pipe 81 c is located below the bottom surface of the cylinder head 15 c, and a joint portion 85 c is connected with the bottom surface of the cylinder head 15 c. One end side of the branched portion 84 c is connected with the branched portion 84 d through the connection pipe G. The other end side of the branched portion 84 c is connected with the branched portion 84 b through the connection pipe G. The branched pipe 81 d is located above the upper surface of the cylinder head 15 d, and a joint portion 85 d is connected with an upper surface of the cylinder head 15 d. One end side of the branched portion 84 d is connected with the branched portion 84 a through the connection pipe G. The other end side of the branched portion 84 d is connected with the branched portion 84 c through the connection pipe G. These connection pipes G are arranged between the adjacent cylinders, and extend in the direction of the rotational shaft 42. As mentioned above, the plural branched pipes 81 a to 81 d are connected with one another.

As illustrated in FIGS. 1 to 3, the fan F faces at least a part of the air pipe 80. Specifically, the branched portions 84 b and 84 d face the fan F, whereas the branched portions 84 a and 84 c do not face the fan F directly. In other, words, the cylinder 10 a is sandwiched between the branched portion 84 a and the fan F, and the cylinder 10 c is sandwiched between the branched portion 84 c and the fan F. Also, the branched portion 84 b is sandwiched between the fan F and the cylinder 10 b, and the branched portion 84 d is sandwiched between the fan F and the cylinder 10 d. The branched portions 84 a and 84 c are an example of a first air portion. The branched portions 84 b and 84 d are an example of a second air portion. The connection pipe G is an example of a communication portion communicating the first and second air portion with each other.

Further, the fan F faces at least parts of the cylinder bodies 12 a to 12 d. The rotation of the fan F can cool the air pipe 80, the four cylinder bodies 12 a to 12 d, and the crankcase 20. A piston 25 a as will be described later reciprocates within the cylinder 10 a and the like. The cylinder 10 a, the crankcase 20, the branched portion 84 a to 84 d, and the like are made of metal such as aluminum having a good heat radiation characteristic.

FIG. 4 is a sectional view taken along line A-A of FIG. 1. Firstly, the motor M will be described. The motor M includes: coils 30, a rotor 40, a stator 50, and a printed circuit board PB. The stator 50 is made of metal. The stator 50 is secured to the crankcase 20. The plural coils 30 are wound around the stator 50. The coils 30 are electrically connected with the printed circuit board PB. As for the printed circuit board PB, conductive patterns are formed on an insulating board having rigidity. A non-illustrated power supply connector for supplying power to the coils 30, a signal connector, and other electronic parts are mounted on the printed circuit board PB. For example, the electronic part is an output transistor (a switching element) such as an FET for controlling an energized state of the coils 30, or a capacitor. The coils 30 are energized, so the stator 50 is energized.

The rotor 40 includes: a rotational shaft 42; a yoke 44; and one or plural permanent magnets 46. The rotational shaft 42 is rotationally supported by plural bearings arranged within the crankcase 20. The yoke 44 is secured to the rotational shaft 42 through a hub 43, so the yoke 44 rotates together with the rotational shaft 42. The yoke 44 has a substantially cylindrical shape and is made of metal. One or plural permanent magnets 46 are secured to the inner circumferential side of the yoke 44. The permanent magnets 46 face the outer circumferential surface of the stator 50. The coils 30 are energized, so the stator 50 is energized. Thus, the magnetic attractive force and the magnetic repulsive force are generated between the permanent magnets 46 and the stator 50. This magnetic force allows the rotor 40 to rotate with respect to the stator 50. As mentioned above, the motor M is an outer rotor type motor in which the rotor 40 rotates.

The fan F, secured to the motor M, includes: a body portion FM having a substantially cylindrical shape; a ring portion FR formed at the outside of the body portion FM; and plural blade portions FB formed between the body portion FM and the ring portion FR. The body portion FM of the fan F is secured to the yoke 44 of the rotor 40 by, for example, press fitting, an adhesive bond, or screwing to the hub 43 with the rotor 40. Specifically, the inner diameter of the body member FM fits the outer diameter of the yoke 44. The Fan F is made of resin.

As illustrated in FIG. 4, the fan F and the motor M are arranged in the radial direction of the fan F when viewed from the cross section including the axis of the motor M. Specifically, the fan F, the coils 30, the rotor 40, and the stator 50 are arranged in the radial direction of the fan F. Thus, for example, as compared with a case where the fan F is arranged at the end of the motor M in the axial direction (the left side in FIG. 4) and is secured to the front end of the rotational shaft, the compressor A according to the present embodiment has a reduced thickness in the axial direction. Further, the fan F is close to the air pipe 80 and the cylinders 10 a to 10 d, thereby improving the cooling effects.

Also, in a case where the fan F is arranged at the end of the motor M in the axial direction and is secured to the front end of the rotational shaft, the rotational shaft has to be long. If the rotational shaft is long, it is necessary to provide a large bearing or plural bearings in order to support the rotation of the rotational shaft. In the compressor A according to the present embodiment, the short rotational shaft 42 is employed, thereby supporting the rotational shaft 42 by a small bearing or few bearings. Therefore, the whole weight of the compressor A is reduced.

Next, the inner structure of the cylinder 10 a will be described. A chamber 13 a is formed in the cylinder body 12 a. The chamber 13 a is defined by the space, which is formed within the cylinder body 12 a, and the distal end of the piston 25 a, which reciprocates within the space. The piston 25 a reciprocates in response to the rotation of the motor M, so the capacity of the chamber 13 a increases or decreases. The proximal end of the piston 25 a is located within the crankcase 20 and is connected to the rotational shaft 42 of the motor M through the bearing. Specifically, the proximal end of the piston 25 a is eccentric to the center of the rotational shaft 42, and the piston 25 a reciprocates in response to the rotation of the rotational shaft 42 in the single direction. Likewise, the other cylinders 10 b to 10 d and the other pistons 25 b to 25 d respectively moving therewithin have the same structure. The positional phase difference between the four pistons 25 a to 25 d is 90 degrees.

In the bottom portion of the crankcase 20, an air hole 22 a is formed in the vicinity of the cylinder 10 a. Likewise, an air hole 22 c is formed in the vicinity of the cylinder 10 c. The reciprocation of the piston 25 a permits air to be introduced into the crankcase 20 through the air hole 22 a. The distal end of the piston 25 a is provided with a communication hole 26 a. The end surface of the distal end of the piston 25 a is provided with a non-illustrated valve member for closing the communication hole 26 a. This valve member is formed by elastic material. This valve member opens or closes the communication hole 26 a based on a difference between the internal pressure of the chamber 13 a and the crankcase 20. The valve member allows air to flow from the crankcase 20 side to the chamber 13 a, but restricts air from flowing from the chamber 13 a side to the crankcase 20 side. In the cylinder head 15 a, a communication hole 16 a is provided in a wall portion separating the chamber 13 a from an exhaust chamber 18 a. A non-illustrated valve member is provided at the exhaust chamber 18 a side of the wall portion. This valve member is formed by elastic material. This valve member opens or closes the communication hole 16 a based on a difference between the internal pressure of the chamber 13 a and the exhaust chamber 18 a. The valve member allows air to flow from the chamber 13 a side to the exhaust chamber 18 a side, but restricts air from flowing from the exhaust chamber 18 a side to the chamber 13 a side. The branched portion 84 is communicated with the exhaust chamber 18 a.

The reciprocation of the piston 25 a changes the capacity of the chamber 13 a. In response to this, air is introduced to the chamber 13 a through the inlet port 22 a and the communication hole 26 a and is compressed within the chamber 13 a. The compressed air is introduced into the exhaust chamber 18 through the communication hole 16 a and is discharged to the branched portion 84 a. Specifically, while the capacity of the chamber 13 a is being increased by the piston 25 a, a valve member provided in the piston 25 a opens the communication hole 26 a, and air is introduced to the chamber 13 a. While the capacity of the chamber 13 a is being decreased by the piston 25 a, this valve member closes the communication hole 26 a. Also, while the capacity of the chamber 13 a is being increased by the piston 25 a, the valve member provided at the cylinder head 15 a side closes the communication hole 16 a, and while the capacity of the chamber 13 a is being decreased by the piston 25 a, this valve member opens the communication hole 16 a.

Likewise, the other cylinders have the same structure. Thus, air introduced into the crankcase 20 through the air holes 22 a and 22 c formed therein is compressed by the reciprocation of the pistons 25 a to 25 d, and is discharged outside through the air pipe 80.

Additionally, when the compressor A is used as a vacuum machine, the air pipe 80 functions as an inlet pipe which guides air from the outside to the cylinders 10 a to 10 d. In this case, the valve member provided within the cylinder 10 a has to be arranged in a manner opposite to the manner of the compressor A, in light of such a direction as to introduce air. Additionally, for another case where the compressor A is used as a vacuum machine, an object device is connected with the inlet port 22 a, whereby the air pipe 80 functions as an outlet port discharging air introduced through the inlet port 22 a. In this case, the valve member provided in the cylinder 10 a may be arranged in the same manner as the compressor A.

Thus, air is adiabatically compressed within the chamber 13 a, so that the temperature of the air within the chamber 13 a becomes high. Thus, the air adiabatically compressed within the cylinder bodies 12 a to 12 d flows into the air pipe 80. For this reason, the temperature of the air pipe 80 into which high-temperature air flows also becomes high. The rotation of the fan F can cool the air pipe 80, and air flowing thereinto, too. For example, when the compressed air has high temperature, a problem may arise, depending on the purpose of using the compressor A. The compressor A according to the present embodiment can cool the compressed air as mentioned above, so the purpose of using the compressor A is not limited. Additionally, in a case where the compressor A is used as a vacuum machine, air is introduced into the cylinder 10 a and the like through the air pipe 80, or air discharged from the cylinder 10 a and the like flows into the air pipe 80. Air to be introduced into the cylinder 10 a is cooled by rotating the fan F.

As illustrated in FIG. 4, a lip seal 27 having a ring shape is provided at the distal end of the piston 25 a. The lip seal 27 slides on the inner wall of the cylinder body 12 a in response to the reciprocation of the piston 25 a. The lip seal 27 prevents air from leaking through a gap between the distal end of the piston 25 a and the inner wall of the cylinder body 12 a. The lip seal 27 is made of resin. The lip seal 27 of the piston 25 a slides on the inner wall of the cylinder body 12 a, so that the cylinder body 12 a and the piston 25 a heat. When such a high temperature state is kept, the life of the lip seal 27 or another part might deteriorate.

The cylinders 10 a to 10 d can be cooled by the fan F, thereby suppressing such an above problem. Additionally, although the branched portion 84 b is arranged between the fan F and the cylinder 10 b, air directly or indirectly flows to the cylinder 10 b and the cylinder head 15 b from the fan F, thereby cooling the cylinder 10 b.

Also, the air pipe 80 is connected with the cylinders 10 a to 10 d. Therefore, the fan F cools the air pipe 80, whereby the cylinders 10 a to 10 d can be cooled.

The fan F partially faces the cylinder heads 15 a and 15 c. Thus, the rotation of the motor M allows the fan F to also cool the cylinder heads 15 a and 15 c. This promotes cooling of the cylinders 10 a and 10 c.

Also, the fan F is attached with the rotor 40, so the fan F is close to the cylinders 10 a to 10 d. Thus, the fan F effectively cools the cylinders 10 a to 10 d.

Air directly or indirectly flows toward the crankcase 20 and the motor M from the fan F. This can also cool the crankcase 20 and the motor M. The cooling of the crankcase 20 can suppress the wear between parts of the rotational shaft 42 and the piston 25 connected with each other within the crankcase 20, and can suppress the wear of the bearing, arranged within the crankcase 20, of the rotational shaft 42. Also, the motor M itself is cooled to suppress heat from transferring to the cylinder 10 and the crankcase 20. Thus, the whole compressor A can be cooled.

Therefore, the fan F can cool the cylinders 10 a to 10 d, the crankcase 20, and the motor M. Thus, it is not necessary to provide fans respectively cooling these parts, unlike a device using a conventional compressor or a conventional vacuum machine. Thus, as for the compressor A or a vacuum machine according to the present embodiment, the number of the parts is reduced and the manufacturing cost is reduced.

As illustrated in FIGS. 2 and 3, the cylinders 10 b and 10 c are provided such that a distance between the fan F and the cylinder 10 b is different from a distance between the fan F and the cylinder 10 c. Specifically, the distance between the cylinder 10 c and the fan F is shorter than the distance between the cylinder 10 d and the fan F. A distance between the cylinder 10 a and the fan F is shorter than a distance between the cylinder 10 b and the fan F. The distance between the cylinder 10 a and the fan F is equal to the distance between the cylinder 10 c and the fan F. The distance between the cylinder 10 b and the fan F is equal to the distance between the cylinder 10 d and the fan F. The reason will be described below.

The pistons 25 a and 25 c have the same shape and are oppositely arranged as illustrated in FIG. 4, the cylinders 10 a and 10 c respectively housing the pistons 25 a and 25 c can be arranged at the same height position. Likewise, the pistons 25 b and 25 d have the same shape and are oppositely arranged, the cylinders 10 b and 10 d can be arranged at the same height position. Here, the pistons 25 a to 25 d have the same shape and the same size. Also, as illustrated in FIG. 4, the rotational shaft 42 is connected with the pistons 25 a, 25 c, 25 b, and 25 d in this order from one end, connected with the fan F, of the rotational shaft 42 and to the other end. Thus, the positions of the cylinder 10 b and 10 d, which respectively house the pistons 25 b and 25 d and which are connected with the other end side of the rotational shaft 42, are lower than the positions of the cylinders 10 a and 10 c, which respectively house the pistons 25 a and 25 c. Thus, the cylinders 10 b and 10 d are distant from the fan F, as compared with the cylinders 10 a and 10 c. In the present embodiment, the branched portion 84 b is arranged between the fan F and the cylinder 10 b comparatively distant therefrom, and the branched portion 84 d is arranged between the fan F and the cylinder 10 d comparatively distant therefrom. Thus, the dead space is effectively used.

Also, the connection pipe G extending in the direction of the rotational shaft 42 is arranged between the adjacent cylinders 10 a and 10 b, thereby effectively use the dead space. As mentioned above, the air pipe 80 is partially arranged in the dead space which is provided between the fan F and the cylinder 10 b and which is provided between the adjacent cylinders 10 a and 10 b, whereby the full length of the air pipe 80 is ensured while the whole size of the compressor A is suppressed from increasing. Therefore, the high-temperature air flowing into the air pipe 80 can be cooled as long as possible.

Also, the motor M is the outer rotor type motor. The outer rotor type motor has a torque higher than that of an inner rotor type motor, providing that they have the same size. This suitably moves the pistons 25 a to 25 d.

For example, the shape of the air pipe 80 is not limited into a linear shape, in the above embodiment. For example, a meandered shape or a spiral shape may be employed. Such shapes ensure the full length of the air pipe 80, thereby cooling air flowing thereinto.

Second Embodiment

A compressor A′ according to a second embodiment will be described. Additionally, similar components of the compressor according to the first embodiment are designated with similar reference numerals and a description of those components will be omitted. FIGS. 5 and 6 are external views of a compressor A′ according to the second embodiment. An air pipe 80′ is arranged between the fan F and cylinders 10 a′ to 10 d′, and has a ring shape along the outer circumference of the fan F when viewed in the axial direction of the rotation of the fan F. Branched pipes 81 a′ to 81 d′ include branched portions 84 a′ to 84 d′ arranged above the upper surfaces of cylinder heads 15 a′ to 15 d′, respectively. The branched portions 84 a′ to 84 d′ are connected with the cylinder heads 15 a′ to 15 d′ through joint portions 85 a′ to 85 d′, respectively.

The branched portions 84 a′ and 84 b′ are connected by a connection pipe G′, and the branched portions 84 b′ and 84 c′ also are connected by the connection pipe G′. The air pipe 80′ is formed into a ring shape arranged between the fan F and the cylinders 10 a′ to 10 d′ in the above way. Therefore, the substantially whole air pipe 80′ is exposed to air flown from the fan F, thereby effectively cooling air flowing into the air pipe 80′.

Additionally, although the air pipe 80′ is arranged between the fan F and the cylinders 10 a′ to 10 d′, air directly or indirectly flows toward the cylinders 10 a to 10 d from the fan F, thereby cooling the cylinders 10 a′ to 10 d′.

As illustrated in FIG. 6, a distance between the fan and each of the cylinders 10 a′ to 10 d′ is equal.

That is, the cylinders 10 a′ to 10 d′ are positioned at the same height. This can evenly cool the cylinders 10 a′ to 10 d′.

FIG. 7 is a sectional view taken along line B-B of FIG. 5. Unlike the first embodiment, the rotational shaft 42 is connected with pistons 25 b′, 25 a′, 25 c′, and 25 d′ in this order from one end to the other end of the rotational shaft 42. Herein, the pistons 25 a′ and 25 c′ have the same shape, and are oppositely arranged to be connected with the rotational shaft 42. Likewise, the pistons 25 b′ and 25 d′ have the same shape, and are oppositely arranged to be connected with the rotational shaft 42. Here, each shape of the pistons 25 b′ and 25 d′ is different from each shape of the pistons 25 a′ and 25 c′. That is, in order to arrange all of the cylinders 10 a′ to 10 d′ in the same height, each shape of the pistons 25 b′ and 25 d′ is different from each shape of the pistons 25 a′ and 25 c′.

Additionally, the air pipe 80′ has a ring shape, so the pressure loss is reduced as compared with a case where a shape is complicated.

Third Embodiment

A compressor A″ according to a third embodiment will be described. FIGS. 8 and 9 are external views of the compressor A″ according to the third embodiment. A body portion FM′ of a fan F′ is provided with plural holes FH. Further, a yoke 44′ is provided with holes positionally corresponding to the holes FH. Therefore, heat radiation of the motor through the holes FH can be promoted.

An air pipe Blab is arranged between cylinder heads 15 a″ and 15 b″, and an air pipe 81 cd is arranged between cylinder heads 15 c″ and 15 d″. The air pipe Blab is communicated within the cylinder heads 15 a″ and 15 b″, and linearly extends. Likewise, the air pipe 81 cb is communicated within the cylinder heads 15 c″ and 15 d″, and linearly extends. The air pipes 81 ab and 81 cd are made of metal such as aluminum or stainless steel, but are not limited to these. The air pipe 81 ab is inserted into holes respectively formed at side surfaces of the cylinder heads 15 a″ and 15 b″. The air pipe 81 cd is inserted into holes respectively formed at side surfaces of the cylinder heads 15 c″ and 15 d″.

As illustrated in FIG. 8, the air pipes 81 ab and 81 cd partially face the fan F′. Specifically, the air pipes 81 ab and 81 cd face the ring portion FR. Air is blown toward the air pipe 81 ab and 81 cd from the fan F′, thereby cooling air flowing into the air pipes 81 ab and 81 cd. Also, the adjacent cylinder heads 15 a″ and 15 b″ are connected through the single air pipe 81 ab. Thus, the number of parts is reduced, and the number of assembling processes is reduced.

As illustrated in FIG. 9, a hole 19 a″ is formed in the cylinder head 15 a″ at the side surface facing the cylinder head 15 d″. Likewise, as not illustrated in FIG. 9, a hole is formed in the cylinder head 15 d″ at the side surface facing the cylinder head 15 a″. These holes function as outlet ports discharging air. Additionally, a hole 19 b″ is formed in the cylinder head 15 b″ at the side surface facing the cylinder head 15 c″. As not illustrated in FIG. 9, a hole is formed in the cylinder head 15 c″ at the side surface facing cylinder head 15 b″. These holes are closed by inserting bolts thereinto.

Thus, air flows into the air pipe 81 ab from the cylinder head 15 b″ side to the cylinder head 15 a″ side. Air flows into the air pipe 81 cd from the cylinder head 15 c″ side to the cylinder head 15 d″ side. Thus, in the cylinder head 15 a″, the air compressed in and discharged from each of the cylinders 10 a″ and 10 b″ flows together. In the cylinder head 15 d″, the air compressed in and discharged from each of the cylinders 10 c″ and 10 d″ flows together. Therefore, the cylinder heads 15 a″ and 15 d″ function as making air compressed in and discharged from the different cylinders flow together. Thus, a pipe making such air flow together is not needed, thereby reducing the number of pipes.

Additionally, like the first and second embodiments, the bottom surface of a crankcase 20″ is formed with an inlet port for introducing air into the crankcase 20″.

In the first and second embodiments, the fan F′ may be employed instead of the fan F, and the yoke according to the third embodiment may be employed instead of the yoke 44.

Fourth Embodiment

A compressor A′″ according to a fourth embodiment will be described. FIGS. 10 and 11 are external views of the compressor A′″ according to the fourth embodiment. An air pipe 81 ab′ is arranged between cylinder heads 15 a′″ and 15 b′″, an air pipe 81 bc′ is arranged between cylinder heads 15 b′″ and 15 c′″, and an air pipe 81 cd′ is arranged between cylinder heads 15 c′″and 15 d′″. Each of the air pipes 81 ab′, 81 bc′, and 81 cd′ are curved by approximately 90 degrees. For example, the air pipe 81 ab′, 81 bc′, and 81 cd′ are made of metal. As illustrated in FIG. 11, a hole 19 a′″ is formed in the cylinder head 15 a′″ at a side surface facing the cylinder head 15 d′″. The hole 19 a′″ functions as an outlet port. Thus, air flows into the cylinders 10 d′″, 10 c′″, 10 b′″, and 10 a′″ in this order.

The fan F′ does not face the air pipes 81 ab′, 81 bc′, and 81 cd′ when viewed in the axial direction of the rotational shaft 42 as illustrated in FIG. 10. However, the fan F′ faces any one of the air pipes 81 ab′, 81 bc′, and 81 cd′ when viewed in the oblique direction with respect to the axial direction of the rotational shaft 42. This is because there is no member between the ring portions FR and the air pipes 81 ab′, 81 bc′, and 81 cd′. Because the fan F′ faces the air pipes 81 ab′, 81 bc′, and 81 cd′ in the above manner, thereby cooling air flowing into the air pipe 81 ab′, 81 bc′, and 81 cd′.

While the exemplary embodiments of the present invention have been illustrated in detail, the present invention is not limited to the above-mentioned embodiments, and other embodiments, variations and modifications may be made without departing from the scope of the present invention.

The number of the cylinders is not limited to four. The fans F and F′ face the cylinder bodies 12 a to 12 d in the above embodiments. However, the blade portion FB or the like may be made large such that the fans F and F′ face the cylinder heads 15 a to 15 d.

In the above embodiments, the crankcase 20 is provided with the inlet port 22 a for introducing air into the chamber 13 a from the outside. However, the present invention is not limited to this. For example, the cylinder 10 a may be provided with such a hole.

In the first and second embodiments, plural pipes are connected via the connection pipe G made of rubber. However, the present invention is not limited to this. For example, plural pipes may be directly jointed to be connected with each other. 

What is claimed is:
 1. A compressor comprising: a cylinder; a piston arranged within in the cylinder; an outer rotor type motor causing the piston to reciprocate within the cylinder; an air pipe communicated with the cylinder such that air flows into the air pipe in response to reciprocation of the piston; and a fan secured to a rotor of the outer rotor type motor and facing at least a part of the air pipe.
 2. The compressor of claim 1, wherein the cylinder includes adjacent first and second cylinders, and the air pipe includes: a first air portion communicated within the first cylinder sandwiched between the first air portion and the fan; a second air portion communicated within the second cylinder and sandwiched between the fan and the second cylinder; and a communication portion extending between the first and second cylinders and communicating the first and second cylinders with each other.
 3. The compressor of claim 2, wherein the first cylinder is close to the fan, and the second cylinder is distant from the fan.
 4. The compressor of claim 1, wherein the air pipe is provided between the cylinder and the fan, and has a substantially ring shape along an outer circumference of the fan when viewed in an axial direction of rotation of the fan.
 5. The compressor of claim 1, wherein the cylinder includes adjacent first and second cylinders, and the air pipe communicates the first and second cylinders within each other.
 6. The compressor of claim 1, wherein the fan is arranged in a radial direction of the rotor.
 7. A vacuum machine comprising: a cylinder; a piston arranged within in the cylinder; an outer rotor type motor causing the piston to reciprocate within the cylinder; an air pipe communicated with the cylinder such that air flows into the air pipe in response to reciprocation of the piston; and a fan secured to a rotor of the outer rotor type motor and facing at least a part of the air pipe.
 8. The vacuum machine of claim 7, wherein the cylinder includes adjacent first and second cylinders, and the air pipe includes: a first air portion communicated within the first cylinder sandwiched between the first air portion and the fan; a second air portion communicated within the second cylinder and sandwiched between the fan and the second cylinder; and a communication portion extending between the first and second cylinders and communicating the first and second cylinders with each other.
 9. The vacuum machine of claim 8, wherein the first cylinder is close to the fan, and the second cylinder is distant from the fan.
 10. The vacuum machine of claim 7, wherein the air pipe is provided between the cylinder and the fan, and has a substantially ring shape along an outer circumference of the fan when viewed in an axial direction of rotation of the fan.
 11. The vacuum machine of claim 7, wherein the cylinder includes adjacent first and second cylinders, and the air pipe communicates the first and second cylinders within each other.
 12. The vacuum machine of claim 7, wherein the fan is arranged in a radial direction of the rotor. 